I'm thinking of buying the new SONOS Playbar and will also need the SONOS Bridge. I currently have an Apple Time Machine that is connected to my Comcast cable modem through an ethernet cable. I currently use just the TV's built-in speakers. Does anyone know if the SONOS Bridge will work properly if I connect it to the Time Capsule with an ethernet cable?

Are you using the Time Capsule as your router? If so, then your Sonos system will work properly. One Sonos component must be hard-wired to your home network. If you can hard-wire the Playbar to your network you won't need the bridge.